1. Field of the Invention
The present invention generally relates to systems and methods of document validation and authentication. More particularly, the present invention relates to the use of embedded optical signatures in documents primarily for the purposes of authentication, validation, and copy verification.
2. Description of the Related Art
There are several methods known to embed security measures into a document to help prove that the document is authentic. The most basic methods are to impose or emboss a visible seal on the document. It is also known to use a watermark or a ribbon in the substrate of the document, or use color shifting ink, all of which are readily visible to a person viewing the document. There are other methods to maintain document authenticity which are not readily visible to a viewer, such as micro printing, or the use of heat (or light) sensitive ink.
One particularly important area for document authentication concerns lottery tickets. In most instances, mere possession of a winning lottery ticket entitles the holder to the winnings. Thus, authentication of the presented lottery ticket is critically important. For example, lottery on-line tickets which are common in many countries and states are, by necessity, printed and presented to the purchaser in real-time with transactional data printed on the lottery ticket via a thermal or impact printer. To enhance security, lotteries typically use preprinted ticket stock with serial numbering on the back of the printing substrate as well as fluorescent and other inks on the ticket substrate to help prove authenticity and integrity. The preprinted serial numbering provides much of the security in determining the authenticity of a winning ticket because the distribution of the preprinted serial number ticket stock is maintained by an entity separate from the one controlling the printing of transactional data. When a winning ticket is presented for redemption, an audit trail can be established between the ticket stock serial number and the transactional data. However, this added paper stock security has the disadvantage of high cost, as well as the logistics of tracking the ticket stock. Also, the labor intensive nature of correlating the ticket stock to an on-line lottery ticket printed at a given retailer at a given time typically prohibits the method's use for all but high-tier winning tickets. Moreover, existing commercial barcodes and serial numbers only cover a portion of the ticket and are relatively easy to remove and replace.
Another problem is that it is essential for an on-line lottery ticket to be proven both to exhibit authenticity (i.e., proof that it was created by the lottery system at the appropriate time) and integrity (i.e., that the ticket has not been modified by the player—it is in its original unmodified condition). Preprinted ticket stock and associated commercial barcodes simply prove that a ticket was printed at a given retailer during a given time period. Also, mere proof of authenticity does not address the problem of an insider with immediate knowledge of the winning ticket's number simply acquiring ticket stock from the retailer and printing a fraudulent winning ticket indicia. The concept of authenticity is also important to the lottery customer as he is also protected from the lottery authority falsely denying that the ticket is authentic.
Document authentication and integrity are particularly difficult with lottery “scratch-off” tickets. The scratch-off ticket has an array of playing indicia covered with a removable covering, typically a layer of latex, and the player removes the scratch-off layer to determine if the ticket contains winning indicia. The system to validate the winning scratch-off ticket must determine if the scratch-off media has been substantially removed prior to awarding a prize. This step is necessary to ensure that the scratch-off ticket cannot be prescreened by the ticket retailers with only non-winning tickets sold to the general public; i.e., a ticket with a substantial amount of its scratch-off layer removed cannot be sold as a virgin (un-played) ticket. Traditionally, this validation of removal of scratch-off layer was accomplished by requiring the retailer to enter coded information that was hidden under the scratch-off layer. However, this process was labor intensive and time consuming for the retailer. Often, the player does not remove the portion of the scratch-off layer covering the coded information as the revealing of the coded information is not of any value to the player. Furthermore, sometimes the area over the coded information is marked e.g., “VOID IF REMOVED”, to prevent the player from scratching off the layer and attempting to alter the code.
One method that attempted to allow authentication, integrity, and validation of scratch-off lottery tickets entailed hiding a two-dimensional barcode under the ticket's scratch-off medium that could easily be scanned with the proper equipment. However, the equipment required to scan the two dimensional bar code is expensive. Moreover, the hiding of a two-dimensional barcode under the ticket's scratch-off medium still results in the same labor intensive problem for the retailer as players tend to not scratch-off the area of the latex covering the two-dimensional barcode because it is of no interest. A further method to insure authentication, integrity, and validation of scratch-off lottery tickets is electrically scanning the ticket for the presence of electrical signatures in the scratch-off ink as well as the ticket's substrate. However, this method also requires expensive equipment.
When on-line systems for validating lottery tickets are employed, a scratch-off ticket presented for validation has its serial numbered barcode scanned and transmitted, along with other data, to a common Central Site database. If the serial number and other data identify the ticket as a winner and it has not been previously paid, a “pay ticket” authorization is transmitted to the terminal that generated the request.
When dial-up validation systems are employed, the dial-up terminal typically decrypts the information embedded in the scratch-off ticket's barcode to determine if it won a prize and, if so, authorizes payment locally without immediately contacting a Central Site database. Scanned ticket information is then queued in the terminal's buffer and transmitted to a Central Site database periodically—e.g., once or twice a day.
Recent advances in color printers and photocopies have made it relatively easy to produce authentic looking forgeries of scratch-off lottery tickets with their scratch-off coating completely removed. These forgeries can then be presented for payment to unsuspecting retailers. In the case of on-line validation systems, the forgery is first presented to a retailer. On-line systems derive their security by insuring that the ticket was not previously paid. So, the forged ticket's barcode is authenticated and the winnings are paid. After the forgery has been paid and the forged ticket destroyed, the authentic ticket is then presented for payment at a different retailer. The system will not authorize payment of this ticket, because the Central Site database will indicate that it was already paid. However, since this second ticket is truly authentic, it can then be submitted for payment to the Lottery without any fear of detection of the prior forgery. Thus, with on-line systems, the forger can redeem a scratch-off lottery ticket twice with minimal fear of detection.
With a dial-up validation system, the problem becomes worse. Since the terminal does not immediately transmit the validation data to the Central Site, multiple forged tickets can be presented to different terminals at different retailers. As long as the involved terminals have not contacted the Central Site database, the same winning ticket can be paid multiple times.
It is therefore desirable to incorporate an automated validation methodology that would, in addition to simply scanning a scratch-off ticket's barcode, also verify that the ticket presented for validation is, in fact, authentic. Such a validation can be performed by reading electrical signatures embedded in genuine scratch-off lottery tickets that are not present in color forgeries. However, this technique requires relatively expensive and specialized validation equipment.
Accordingly, it would be advantageous to provide a method for document validation embedded on the substrate of the document that is visible to equipment viewing the document. Said method should not require a large surface area of view in order to provide the information requisite to validate or authenticate the document. Said method should also not require expensive validation equipment. Such method would be particularly well suited for the validation of scratch-off lottery tickets as well as authenticating on-line tickets. It is toward such a method of document security and authentication that the present invention is primarily directed.